Sol 45

MISSION LOG – SOL 45

Another long day of work, another day closer to planting crops. Today was all about turning soil, and all of us were doing that except for Starlight. She was doing this really clever thing with the ceiling crystals, cutting caps off of some of the bigger ones, slicing them into these neat spiky flower shapes, and turning them into some sort of sun relay. Spitfire took them topside and lined them up directly above the cave, and now the cave has light- a lot more light than I’d have expected. Starlight tried to explain- something about extra surface area of the flower-cut crystals- but Spitfire sent her back to the rover before she could finish.

The ponies have done a better job than I’d expected of breaking up the dense Martian soil in the cave. Of course, Starlight’s spell provided a head start, providing a lot of microscopic voids that loosened the dirt enough for our makeshift sled-harrow to get down into it. It also helped Fireball and me shovel out the channels for the ponies’ neat idea for attacking the heat problem in the cave.

On Earth, once you go beyond a certain level below the surface, it begins to get hotter. Our planet has a thin crust and a lot of internal heat. If Mars has any internal heat left, it’s hiding it very, very well. The cave is actually slightly colder than the surface. And since it’s mostly buried under rock, soil and permafrost, warming up the interior means battling one of the worst heat sinks of all time.

The pony solution? Steam heat.

Let me explain the logic. The pony ship mainly relied on their ship’s atmospheric exchange magic for cabin heating. There were only a few emergency space heaters in the ship, and when I tested them they turned out to be just as thirsty for electricity as expected. It’s like they just grabbed a space heater at a flea market or something and stuck it into their ship. Each one sucks up almost 200 watts of electricity. We’re going to use them anyway, because we need all the heat we can get down there.

I could yank the larger heaters from the rovers, but we need those to not freeze driving to and from the cave. Besides, just the little heaters will require eight solar panels from the Hab plus one of my hydrogen fuel cells to keep them running at night. More heaters like that will take the Hab below a safety margin I’m just not ready to exceed yet.

We have the pony ship’s air working again, and I’ve taken advantage of that at the Hab to shut down all the air systems and do a full diagnostic. (Everything checks out, by the way.) That means we can install the pony life support box in the cave and use it to fill it up with nice temperate pony air. Problem solved, right?

Well, not really. There’s hundreds of meters of geode cave beyond this first chamber that will be Fireball’s dinner for the next four years. Also, the roof of the chamber is several meters high at its highest point. The warm air will circulate back in the cave and up to the ceiling, and there’s dick we can do about that. That means the air will cool, sink, and circulate back to freeze the crops.

That’s entropy, folks- even when you get a free lunch, there ain’t no free lunch. All we can do is improvise a thermal blanket from pony ship insulation, hang it over the entrance to the next chamber, and hope for the best.

But in addition to providing air, the pony life support provides water- both cold and hot, because hot water is what the ponies use to reconstitute or heat up meals in flight. The ponies have kept the hot water deactivated because, up to now, all we’ve needed is cold water, and the hot water flow is about one-fifth that of the cold water.

Why is this, you ask? Because although the ship only had a few emergency heaters, it had a lot of cooling hoses and pipes. In space you don’t have air or water to equalize heat. You have one side of your ship baking in the sun (if you’re lucky enough to be near the sun) and the other side freezing in shadow. This heat differential is bad for equipment and can even endanger the crew, so there are ways to deal with it. Insulation works, and the old “barbecue roll” used by Apollo works just fine, but in this case the ponies went with a heat exchanger system tucked between the outer hull and the pressurized compartments- all provided with fluid from the ship’s cold water supply.

Water is definitely not the coolant NASA would have chosen. There are lots of chemicals which have a wider range of liquid states and a greater heat-exchange efficiency. But the ponies have all the water they want practically free and can replenish it in-flight if there’s a leak, and apparently they can’t do that with the other options. (Besides, I can’t help feeling like Dragonfly or Fireball might be tempted to drink the radiator fluid.)

As a result, there are dozens of meters of plumbing, all with fittings designed to fit the cold water terminal on the life control box. And today Dragonfly fitted them all together into long rows, and Fireball and I buried them all a couple feet into the soil. There’s one fitting sticking up at one end to hook to the life support box and another fitting that will have a valve. That’ll be left open to let water circulate through the system, and the outflow will be used to water crops or just allowed to trickle off downstream into the back of the cave.

The neat trick- and the ponies have already arranged for this with their folks back home- is that the cold water and hot water can be switched. All it takes is swapping two crystals back home. So instead of cold water suitable for redistributing heat under a spaceship’s skin, the pipes will be filled with literally boiling water at one end and will release barely-above-freezing water at the other end, if it works.

Net result: the cave will never be tropical, and we’ll probably wear our suits in here just for comfort- not a phrase you normally hear from an astronaut. But the actual ground where the plants will be rooted should be warm enough for them to live. And some of that subsurface heat will spread above the surface and add to what the air, the heaters, and Starlight’s magical sunlight system provide, and that in theory should protect the plants above ground.

The main problem with this system is that it seriously constrains the area we can cultivate. The chamber is twenty-one meters wide at its widest point and about one hundred ten meters from the inner airlock doors to the narrow bit at the back. Eyeballing it, it’s a bit less than half an acre. But the area covered by the improvised hydronic heat system is a lot smaller- an area of about sixteen meters wide by forty long, or six hundred forty square meters.

Granted, that is a huge improvement over the Hab. My math shows that, if the field is one-quarter potatoes and the rest alfalfa, the cave would be enough by itself for an almost indefinitely sustainable food supply. But there are problems, of course, the biggest being that almost three-quarters of the ground in the room will be sucking away heat from the remaining one-quarter. Ironically, this cave is too damn big.

But it’s what we have. The next chamber is a forest of shafts of crystal- there must have been a mineral spring in that chamber for a while before it merged with the others. Getting equipment through that into the next room would be a major pain- and so would getting harvests out again. And if something does go wrong with this cave, we really do want to be as close to the exit as possible.

Tomorrow we hook up the electrical systems and life support, turn it on, and leave. There’s going to be a huge wind when the air comes in, and we really don’t want to be around for that. After that we take a couple of days off to let our brilliant improvisation do whatever it’s going to do, and then- assuming nothing new explodes in our faces- we take the surplus cultured soil out there, mix it with the harrowed topsoil, and begin planting seeds.

Two days in the Hab suits me just fine. I’ve been burning through CO2 filters- curse you cheap idiot government contractors! Staying inside means I’m not using more filters.. Besides, my potato seed crop has sprouted, and I’d like to spend a bit of time giving my future food supply some TLC.

And maybe we can have a marathon TV day and consign the Partridge Family back to the Stygian depths of the 1970s whence they came, never to return. That’s one thing I honestly like about Dukes of Hazzard: no twee children. Seriously, if I want any more overwhelming cuteness, I’ll…

… yeah, who am I kidding? The alien commander is pink and has eyes half the size of her head. Even the insect-like horror has puppy-dog eyes (without pupils). I’m going to be the first human to contract diabetes on Mars.